处理一个简单的 ADC 项目,从多个通道上的分压器读取电压。我在商业且制作精良的 PCB 上使用 STM32f103rb。我正在读取 PORTA 上的引脚,以下引脚工作并返回电压:
PA0、PA1、PA4、PA5、PA6、PA7。
但是,以下引脚不起作用并返回大约 2000-2700 的原始值:
PA8、PA11 和 PA12。
项目的性质和 PCB 是固定设计的事实意味着我们被这些引脚选择所困扰。数据表非常具体地说明这些引脚可用作 AIN。所有设置和配置均按照标准 STM32,取自基本示例代码并为我们的目的而修改。包含的代码是我们为了寻找原因而制作的调试版本,但无济于事。
已测量引脚上的电压,并且对于分压器的类型是正确的。
任何帮助将不胜感激。
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "stdio.h"
#include "stdlib.h"
// Standard STM peripheral config functions
void RCC_Configuration(void);
void GPIO_Configuration(void);
// ADC config - STM example code
void NEW_ADC_Configuration(void);
// Function to read ADC channel and output value
u16 NEW_readADC1(u8 channel);
// Variables
double voltage_su; // Variable to store supply voltage
double voltage7;
double voltage8;
//*****************************************************************************
// Main program
int main(void)
{
// Initialise peripheral modules
RCC_Configuration();
GPIO_Configuration();
NEW_ADC_Configuration();
// Infinate loop
while (1)
{
// Get value of supply voltage and convert
voltage_su = (((3.3 * NEW_readADC1(ADC_Channel_12)) / 4095));
}
}
//*****************************************************************************
// STM RCC config
void RCC_Configuration(void)
{
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE); // Connect PORTC
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); // Connect PORTB...
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); // Connect PORTA...
}
//*****************************************************************************
// STM GPIO config
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure; // Value for setting up the pins
// Sup
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
//*****************************************************************************
void NEW_ADC_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
ADC_InitTypeDef ADC_InitStructure; // Varibale used to setup the ADC
RCC_ADCCLKConfig(RCC_PCLK2_Div4); // Set ADC clock to /4
// Enable ADC 1 so we can use it
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
// Conenct the port A to peripheral clock
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
// Restore to defaults
ADC_DeInit(ADC1);
/* ADC1 Configuration ----------------------------------------------------*/
ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
// Scan 1 at a time
ADC_InitStructure.ADC_ScanConvMode = DISABLE;
// No continuous conversions - do them on demand
ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
// Start conversion on software request - not bu external trigger
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
// Conversions are 12 bit - put them in the lower 12 bits of the result
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
// How many channels are to be sued by the sequencer
ADC_InitStructure.ADC_NbrOfChannel = 1;
// Setup ADC
ADC_Init(ADC1, &ADC_InitStructure);
// Enable ADC 1
ADC_Cmd(ADC1, ENABLE);
// Enable ADC1 reset calibaration register
ADC_ResetCalibration(ADC1);
// Check end of reset calib reg
while(ADC_GetResetCalibrationStatus(ADC1));
//Start ADC1 calib
ADC_StartCalibration(ADC1);
// Check the end of ADC1 calib
while(ADC_GetCalibrationStatus(ADC1));
}
//*****************************************************************************
// Function to return the value of ADC ch
u16 NEW_readADC1(u8 channel)
{
// Config the channel to be sampled
ADC_RegularChannelConfig(ADC1, channel, 1, ADC_SampleTime_239Cycles5);
// Start the conversion
ADC_SoftwareStartConvCmd(ADC1, ENABLE);
// Wait until conversion complete
while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET);
// Get the conversion value
return ADC_GetConversionValue(ADC1);
}
//*****************************************************************************